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Diffstat (limited to 'crypto/aes_generic.c')
| -rw-r--r-- | crypto/aes_generic.c | 456 |
1 files changed, 456 insertions, 0 deletions
diff --git a/crypto/aes_generic.c b/crypto/aes_generic.c new file mode 100644 index 00000000000..9401dca85e8 --- /dev/null +++ b/crypto/aes_generic.c @@ -0,0 +1,456 @@ +/* + * Cryptographic API. + * + * AES Cipher Algorithm. + * + * Based on Brian Gladman's code. + * + * Linux developers: + * Alexander Kjeldaas <astor@fast.no> + * Herbert Valerio Riedel <hvr@hvrlab.org> + * Kyle McMartin <kyle@debian.org> + * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API). + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * --------------------------------------------------------------------------- + * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK. + * All rights reserved. + * + * LICENSE TERMS + * + * The free distribution and use of this software in both source and binary + * form is allowed (with or without changes) provided that: + * + * 1. distributions of this source code include the above copyright + * notice, this list of conditions and the following disclaimer; + * + * 2. distributions in binary form include the above copyright + * notice, this list of conditions and the following disclaimer + * in the documentation and/or other associated materials; + * + * 3. the copyright holder's name is not used to endorse products + * built using this software without specific written permission. + * + * ALTERNATIVELY, provided that this notice is retained in full, this product + * may be distributed under the terms of the GNU General Public License (GPL), + * in which case the provisions of the GPL apply INSTEAD OF those given above. + * + * DISCLAIMER + * + * This software is provided 'as is' with no explicit or implied warranties + * in respect of its properties, including, but not limited to, correctness + * and/or fitness for purpose. + * --------------------------------------------------------------------------- + */ + +/* Some changes from the Gladman version: + s/RIJNDAEL(e_key)/E_KEY/g + s/RIJNDAEL(d_key)/D_KEY/g +*/ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/crypto.h> +#include <asm/byteorder.h> + +#define AES_MIN_KEY_SIZE 16 +#define AES_MAX_KEY_SIZE 32 + +#define AES_BLOCK_SIZE 16 + +/* + * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) + */ +static inline u8 +byte(const u32 x, const unsigned n) +{ + return x >> (n << 3); +} + +struct aes_ctx { + int key_length; + u32 buf[120]; +}; + +#define E_KEY (&ctx->buf[0]) +#define D_KEY (&ctx->buf[60]) + +static u8 pow_tab[256] __initdata; +static u8 log_tab[256] __initdata; +static u8 sbx_tab[256] __initdata; +static u8 isb_tab[256] __initdata; +static u32 rco_tab[10]; +static u32 ft_tab[4][256]; +static u32 it_tab[4][256]; + +static u32 fl_tab[4][256]; +static u32 il_tab[4][256]; + +static inline u8 __init +f_mult (u8 a, u8 b) +{ + u8 aa = log_tab[a], cc = aa + log_tab[b]; + + return pow_tab[cc + (cc < aa ? 1 : 0)]; +} + +#define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) + +#define f_rn(bo, bi, n, k) \ + bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ + ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ + ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ + ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) + +#define i_rn(bo, bi, n, k) \ + bo[n] = it_tab[0][byte(bi[n],0)] ^ \ + it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ + it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ + it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) + +#define ls_box(x) \ + ( fl_tab[0][byte(x, 0)] ^ \ + fl_tab[1][byte(x, 1)] ^ \ + fl_tab[2][byte(x, 2)] ^ \ + fl_tab[3][byte(x, 3)] ) + +#define f_rl(bo, bi, n, k) \ + bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ + fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ + fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ + fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) + +#define i_rl(bo, bi, n, k) \ + bo[n] = il_tab[0][byte(bi[n],0)] ^ \ + il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ + il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ + il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) + +static void __init +gen_tabs (void) +{ + u32 i, t; + u8 p, q; + + /* log and power tables for GF(2**8) finite field with + 0x011b as modular polynomial - the simplest primitive + root is 0x03, used here to generate the tables */ + + for (i = 0, p = 1; i < 256; ++i) { + pow_tab[i] = (u8) p; + log_tab[p] = (u8) i; + + p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); + } + + log_tab[1] = 0; + + for (i = 0, p = 1; i < 10; ++i) { + rco_tab[i] = p; + + p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); + } + + for (i = 0; i < 256; ++i) { + p = (i ? pow_tab[255 - log_tab[i]] : 0); + q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); + p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); + sbx_tab[i] = p; + isb_tab[p] = (u8) i; + } + + for (i = 0; i < 256; ++i) { + p = sbx_tab[i]; + + t = p; + fl_tab[0][i] = t; + fl_tab[1][i] = rol32(t, 8); + fl_tab[2][i] = rol32(t, 16); + fl_tab[3][i] = rol32(t, 24); + + t = ((u32) ff_mult (2, p)) | + ((u32) p << 8) | + ((u32) p << 16) | ((u32) ff_mult (3, p) << 24); + + ft_tab[0][i] = t; + ft_tab[1][i] = rol32(t, 8); + ft_tab[2][i] = rol32(t, 16); + ft_tab[3][i] = rol32(t, 24); + + p = isb_tab[i]; + + t = p; + il_tab[0][i] = t; + il_tab[1][i] = rol32(t, 8); + il_tab[2][i] = rol32(t, 16); + il_tab[3][i] = rol32(t, 24); + + t = ((u32) ff_mult (14, p)) | + ((u32) ff_mult (9, p) << 8) | + ((u32) ff_mult (13, p) << 16) | + ((u32) ff_mult (11, p) << 24); + + it_tab[0][i] = t; + it_tab[1][i] = rol32(t, 8); + it_tab[2][i] = rol32(t, 16); + it_tab[3][i] = rol32(t, 24); + } +} + +#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) + +#define imix_col(y,x) \ + u = star_x(x); \ + v = star_x(u); \ + w = star_x(v); \ + t = w ^ (x); \ + (y) = u ^ v ^ w; \ + (y) ^= ror32(u ^ t, 8) ^ \ + ror32(v ^ t, 16) ^ \ + ror32(t,24) + +/* initialise the key schedule from the user supplied key */ + +#define loop4(i) \ +{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ + t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ + t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ + t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ + t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ +} + +#define loop6(i) \ +{ t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ + t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ + t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ + t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ + t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ + t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ + t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ +} + +#define loop8(i) \ +{ t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ + t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ + t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ + t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ + t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ + t = E_KEY[8 * i + 4] ^ ls_box(t); \ + E_KEY[8 * i + 12] = t; \ + t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ + t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ + t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ +} + +static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct aes_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *key = (const __le32 *)in_key; + u32 *flags = &tfm->crt_flags; + u32 i, t, u, v, w; + + if (key_len % 8) { + *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; + return -EINVAL; + } + + ctx->key_length = key_len; + + E_KEY[0] = le32_to_cpu(key[0]); + E_KEY[1] = le32_to_cpu(key[1]); + E_KEY[2] = le32_to_cpu(key[2]); + E_KEY[3] = le32_to_cpu(key[3]); + + switch (key_len) { + case 16: + t = E_KEY[3]; + for (i = 0; i < 10; ++i) + loop4 (i); + break; + + case 24: + E_KEY[4] = le32_to_cpu(key[4]); + t = E_KEY[5] = le32_to_cpu(key[5]); + for (i = 0; i < 8; ++i) + loop6 (i); + break; + + case 32: + E_KEY[4] = le32_to_cpu(key[4]); + E_KEY[5] = le32_to_cpu(key[5]); + E_KEY[6] = le32_to_cpu(key[6]); + t = E_KEY[7] = le32_to_cpu(key[7]); + for (i = 0; i < 7; ++i) + loop8 (i); + break; + } + + D_KEY[0] = E_KEY[0]; + D_KEY[1] = E_KEY[1]; + D_KEY[2] = E_KEY[2]; + D_KEY[3] = E_KEY[3]; + + for (i = 4; i < key_len + 24; ++i) { + imix_col (D_KEY[i], E_KEY[i]); + } + + return 0; +} + +/* encrypt a block of text */ + +#define f_nround(bo, bi, k) \ + f_rn(bo, bi, 0, k); \ + f_rn(bo, bi, 1, k); \ + f_rn(bo, bi, 2, k); \ + f_rn(bo, bi, 3, k); \ + k += 4 + +#define f_lround(bo, bi, k) \ + f_rl(bo, bi, 0, k); \ + f_rl(bo, bi, 1, k); \ + f_rl(bo, bi, 2, k); \ + f_rl(bo, bi, 3, k) + +static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *src = (const __le32 *)in; + __le32 *dst = (__le32 *)out; + u32 b0[4], b1[4]; + const u32 *kp = E_KEY + 4; + + b0[0] = le32_to_cpu(src[0]) ^ E_KEY[0]; + b0[1] = le32_to_cpu(src[1]) ^ E_KEY[1]; + b0[2] = le32_to_cpu(src[2]) ^ E_KEY[2]; + b0[3] = le32_to_cpu(src[3]) ^ E_KEY[3]; + + if (ctx->key_length > 24) { + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + } + + if (ctx->key_length > 16) { + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + } + + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + f_nround (b1, b0, kp); + f_nround (b0, b1, kp); + f_nround (b1, b0, kp); + f_lround (b0, b1, kp); + + dst[0] = cpu_to_le32(b0[0]); + dst[1] = cpu_to_le32(b0[1]); + dst[2] = cpu_to_le32(b0[2]); + dst[3] = cpu_to_le32(b0[3]); +} + +/* decrypt a block of text */ + +#define i_nround(bo, bi, k) \ + i_rn(bo, bi, 0, k); \ + i_rn(bo, bi, 1, k); \ + i_rn(bo, bi, 2, k); \ + i_rn(bo, bi, 3, k); \ + k -= 4 + +#define i_lround(bo, bi, k) \ + i_rl(bo, bi, 0, k); \ + i_rl(bo, bi, 1, k); \ + i_rl(bo, bi, 2, k); \ + i_rl(bo, bi, 3, k) + +static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *src = (const __le32 *)in; + __le32 *dst = (__le32 *)out; + u32 b0[4], b1[4]; + const int key_len = ctx->key_length; + const u32 *kp = D_KEY + key_len + 20; + + b0[0] = le32_to_cpu(src[0]) ^ E_KEY[key_len + 24]; + b0[1] = le32_to_cpu(src[1]) ^ E_KEY[key_len + 25]; + b0[2] = le32_to_cpu(src[2]) ^ E_KEY[key_len + 26]; + b0[3] = le32_to_cpu(src[3]) ^ E_KEY[key_len + 27]; + + if (key_len > 24) { + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + } + + if (key_len > 16) { + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + } + + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + i_nround (b1, b0, kp); + i_nround (b0, b1, kp); + i_nround (b1, b0, kp); + i_lround (b0, b1, kp); + + dst[0] = cpu_to_le32(b0[0]); + dst[1] = cpu_to_le32(b0[1]); + dst[2] = cpu_to_le32(b0[2]); + dst[3] = cpu_to_le32(b0[3]); +} + + +static struct crypto_alg aes_alg = { + .cra_name = "aes", + .cra_driver_name = "aes-generic", + .cra_priority = 100, + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = AES_BLOCK_SIZE, + .cra_ctxsize = sizeof(struct aes_ctx), + .cra_alignmask = 3, + .cra_module = THIS_MODULE, + .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), + .cra_u = { + .cipher = { + .cia_min_keysize = AES_MIN_KEY_SIZE, + .cia_max_keysize = AES_MAX_KEY_SIZE, + .cia_setkey = aes_set_key, + .cia_encrypt = aes_encrypt, + .cia_decrypt = aes_decrypt + } + } +}; + +static int __init aes_init(void) +{ + gen_tabs(); + return crypto_register_alg(&aes_alg); +} + +static void __exit aes_fini(void) +{ + crypto_unregister_alg(&aes_alg); +} + +module_init(aes_init); +module_exit(aes_fini); + +MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm"); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_ALIAS("aes"); |